The final single-seat model of the Skyhawk, the A-4M, was developed for the US Marine Corps. When the US Navy began deploying the A-7 Corsair II and the A-4 was replaced by the A-7 as the main carrier-based attack aircraft, the US Marine Corps adopted the A-4M as a land attack aircraft instead of the A-7.

The M model's engine was replaced with a J52-P-408A, and the intake was enlarged accordingly. The outline of the vertical tail was also changed to a more angular shape. A larger windshield was also installed. The electronic equipment was also significantly revamped, with a fin-tip radome on the vertical tail, an LST on the nose, and an ALR-54/ALQ-126 on the nose and tail.